Kuai, Le and Bowman, Kevin W. and Miyazaki, Kazuyuki and Deushi, Makoto and Revell, Laura and Rozanov, Eugene and Paulot, Fabien and Strode, Sarah and Conley, Aandrew and Lamarque, Jean-Francois and Jöckel, Patrick and Plummer, David A. and Oman, Luke D. and Worden, Helen and Kulawik, Susan and Paynter, David and Stenke, Andrea and Kunze, Markus (2020) Attribution of Chemistry-Climate Model Initiative (CCMI) ozone radiative flux bias from satellites. Atmospheric Chemistry and Physics (ACP), 20 (1), pp. 281-301. Copernicus Publications. doi: 10.5194/acp-20-281-2020. ISSN 1680-7316.
![]() |
PDF
- Published version
16MB |
Official URL: https://www.atmos-chem-phys.net/20/281/2020/
Abstract
The top-of-atmosphere (TOA) outgoing longwave flux over the 9.6 µm ozone band is a fundamental quantity for understanding chemistry–climate coupling. However, observed TOA fluxes are hard to estimate as they exhibit considerable variability in space and time that depend on the distributions of clouds, ozone (O3), water vapor (H2O), air temperature (Ta), and surface temperature (Ts). Benchmarking present-day fluxes and quantifying the relative influence of their drivers is the first step for estimating climate feedbacks from ozone radiative forcing and predicting radiative forcing evolution. To that end, we constructed observational instantaneous radiative kernels (IRKs) under clear-sky conditions, representing the sensitivities of the TOA flux in the 9.6 µm ozone band to the vertical distribution of geophysical variables, including O3, H2O, Ta, and Ts based upon the Aura Tropospheric Emission Spectrometer (TES) measurements. Applying these kernels to present-day simulations from the Chemistry-Climate Model Initiative (CCMI) project as compared to a 2006 reanalysis assimilating satellite observations, we show that the models have large differences in TOA flux, attributable to different geophysical variables. In particular, model simulations continue to diverge from observations in the tropics, as reported in previous studies of the Atmospheric Chemistry Climate Model Intercomparison Project (ACCMIP) simulations. The principal culprits are tropical middle and upper tropospheric ozone followed by tropical lower tropospheric H2O. Five models out of the eight studied here have TOA flux biases exceeding 100 mW m−2 attributable to tropospheric ozone bias. Another set of five models have flux biases over 50 mW m−2 due to H2O. On the other hand, Ta radiative bias is negligible in all models (no more than 30 mW m−2). We found that the atmospheric component (AM3) of the Geophysical Fluid Dynamics Laboratory (GFDL) general circulation model and Canadian Middle Atmosphere Model (CMAM) have the lowest TOA flux biases globally but are a result of cancellation of opposite biases due to different processes. Overall, the multi-model ensemble mean bias is −133±98 mW m−2, indicating that they are too atmospherically opaque due to trapping too much radiation in the atmosphere by overestimated tropical tropospheric O3 and H2O. Having too much O3 and H2O in the troposphere would have different impacts on the sensitivity of TOA flux to O3 and these competing effects add more uncertainties on the ozone radiative forcing. We find that the inter-model TOA outgoing longwave radiation (OLR) difference is well anti-correlated with their ozone band flux bias. This suggests that there is significant radiative compensation in the calculation of model outgoing longwave radiation.
Item URL in elib: | https://elib.dlr.de/133324/ | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Document Type: | Article | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Title: | Attribution of Chemistry-Climate Model Initiative (CCMI) ozone radiative flux bias from satellites | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Authors: |
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Date: | 8 January 2020 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Journal or Publication Title: | Atmospheric Chemistry and Physics (ACP) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Refereed publication: | Yes | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Open Access: | Yes | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Gold Open Access: | Yes | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
In SCOPUS: | Yes | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
In ISI Web of Science: | Yes | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Volume: | 20 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
DOI: | 10.5194/acp-20-281-2020 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Page Range: | pp. 281-301 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Publisher: | Copernicus Publications | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
ISSN: | 1680-7316 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Status: | Published | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Keywords: | CCMI, ESCiMo, MESSy, EMAC, ozone, radiative flux, satellite, chemiestry climate modelling, global modelling | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
HGF - Research field: | Aeronautics, Space and Transport | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
HGF - Program: | Space | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
HGF - Program Themes: | Earth Observation | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
DLR - Research area: | Raumfahrt | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
DLR - Program: | R EO - Earth Observation | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
DLR - Research theme (Project): | R - Atmospheric and climate research, R - Project Climatic relevance of atmospheric tracer gases, aerosols and clouds | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Location: | Oberpfaffenhofen | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Institutes and Institutions: | Institute of Atmospheric Physics > Earth System Modelling | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Deposited By: | Jöckel, Dr. Patrick | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Deposited On: | 08 Jan 2020 12:36 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Last Modified: | 08 Jan 2020 12:37 |
Repository Staff Only: item control page